My original question:
>Is there any reason the bytes per inode must be a power of
>2? For my news spool, a number like 3072 (2048+1024) would
>be ideal. Can it be done?
The answer appears to be the value can be any number...
Thanks for all the help.
From: email@example.com (John Justin Hough)
= I have never not made that a power of two, but I have changed the
= logical blocksize and the fragsize or addressability to be 512 bytes.
= It worked. I have a filesystem where pretty much every file is about
= 1100 bytes and I wanted to minimize space wasteage.
= I've also change the number of cylinders per group for a file system
= with very big files - one file per group. This worked too.
From: hal@yin.UCSD.EDU (Hal Skelly)
= There is no real necessity to use powers of 2, it's just convenient. You
= can check inode counts for used and free with the df -i command.
From: Mike Raffety <firstname.lastname@example.org>
= The difference in free disk space between 2048 and 4096 is minimal.
= And yes, they must be a power of two, the way the cylinder group
= structures are designed.
= No, I'm pretty sure the kernel would panic. The main difficulty is that
= many filesystem operations require a poer of two, because they're doing
= bit-shifting (e.g., "a << b") for performance reasons.
= My GUESS is that newfs silently rounds or truncates to a power of two.
From: email@example.com (Syd Weinstein)
= None what so ever. It can be anything, its just a divisor.
From: firstname.lastname@example.org (Jay Lessert)
= newfs' -i flag does not need to be a power of 2. It does, however,
= need to conform to a strange set of rules involving #cyls/cyl group,
= depending on if #sectors/track is even or odd, etc., etc.
= You can play with -i using -N carefully watching the resulting
= mkfs command line to see what it is doing. Changing -c to 8
= is sometimes helpful.
= Yes! it can be done. In fact, mine is around that, and it pretty
= much balances the inodes and disk space.
From: Eckhard.Rueggeberg@ts.go.dlr.de (Eckhard Rueggeberg)
= Yes. Choose ANY number.
From: email@example.com (Donald McLachlan)
= I have always done it as powers of w, but ...
= man newfs says ...
= -i bytes/inode
= This specifies the density of inodes in the file
= system. The default is to create an inode for
= each 2048 bytes of data space. If fewer inodes
= are desired, a larger number should be used; to
= create more inodes a smaller number should be
= and man mkfs (called by newfs) says
= nbpi The number of bytes for which one inode block is allo-
= cated. This parameter is currently set at one inode
= block for every 2048 bytes.
= Neither puts any restrictions on this number, why don't you find an
= unused partition and give it a try.
-- | Robert L. Howard | Georgia Tech Research Institute | | firstname.lastname@example.org | SEAL / ATDD | | (404) 528-7165 | Atlanta, Georgia 30332 | ------------------------------------------------------------------------- | "When we are planning for posterity, we ought to remember that virtue | | is not hereditary." -- Thomas Paine |
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